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Flashcards in metabolic pathways Deck (30)
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1
Q

what metabolic pathways type describes a breakdown of macromolecules to simple precursors

A

catabolic pathway

2
Q

what metabolic pathway type describes a synthesis of macromolecules from simple precursors

A

anabolic pathway

3
Q

what metabolic pathway type is used to generate ATP and reducing powers such as NADH and FADH

A

catabolic pathway

4
Q

what metabolic pathway type uses ATP and reducing powers to drive its reactions

A

anabolic pathway

5
Q

what are examples of catabolic pathways

A

glycolysis
lipolysis
glycogenolysis

6
Q

what are examples of anabolic pathways

A

gluconeogenesis
lipogenesis
glycogenesis
nucleic acid synthesis

7
Q

define what each term means

phosphatase 
phosphroylase 
kinase 
dehydrogenase 
carboxylase 
decarboxylase
A
phosphatase - removes phosphate 
phosphroylase - adds phosphate 
kinase - moves phosphate around 
dehydrogenase - oxidation reduction 
carboxylase - adds carbon 
decarboxylase - removes carbon
8
Q

where does glycolysis occur in the cell

A

cytosol

9
Q

what hormone stimulates glycolysis

what inhibits

A

insulin stimulates

glucagon inhibits

10
Q

what are the 3 rate limiting steps in glycolysis

A

hexokinase
phosphofructokinase
pyruvate kinase

11
Q

what are the energetics of aerobic and anaerobic glycolysis

A

aerobic - net gain of 2 ATP by substrate level phosphorylation and 2 NADH that goes to ETC

anaerobic - net gain of 2 ATP by substrate level phosphorylation

12
Q

what is produced as end product for aerobic and anaerobic glycolysis

A

pyruvate - aerobic

lactate - anaerobic

13
Q

how does pyruvate get to lactate

A

pyruvate + NADH –> lactate + NAD

lactate dehydrogenase

14
Q

cori cycle occurs under what circumstances

where does the cori cycle occur

what are the reactions

A

anaerobic conditions

liver and muscle

muscle generates lactate through anaerobic glycolysis and the lactate is shipped to the liver where the lactate is converted to pyruvate and then converted to glucose via gluconeogensis

15
Q

where does the pyruvate dehydrogenase complex occur in the cell

what is the reaction

what type of reaction is PDC

hormones that inhibit or stimulate

coenzymes

A

mitochondrial matrix

pyruvate + NAD + CoA –> acetyl coA + NADH + CO2

oxidative phsophorylation *
NADH produced
CO2 lost or consumed by pyruvate dehydrogenase to generate acetyl coA

insulin stimulates
glucagon inhibits

NAD - B3
FAD - B2
TPP - B1 
Lipoic acid 
CoA - B5
16
Q

what are other names for TCA

A

krebs cycle
citric acid cycle
tricarboxylic acid cycle

17
Q

where does the krebs cycle occur in the cell

what are its regulatory enzymes

how many steps total

what are the energetics of TCA

where is CO2 released in the TCA

acetyl coA binds to what to start TCA via what enzyme

what are inhibitors of enzyme s

A

mitochondrial matrix

citrate synthase, isocitrate dehydrogenase, alpha ketoglutarate dehydrogenase

8 steps total

1 acetyl coA = 12 ATP
via 3 NADH (9) 1 FADH (2) 1 GTP (1) = 12
NADH and FADH go to ETC to create 11 ATP
GTP goes to substrate level phosphorylation to create 1 ATP

1 molecule of glucose (2 acetyl CoA) = 24 ATP

CO2 released at isocitrate dehydrogenase and alpha ketoglutarate dehydrogenase

acetyl coA + oxaloacetate –> citrate
via citrate synthase

aconitase - fluoroacetate
alpha ketoglutarate - arsenite
succinate dehydrogenase - malonate

18
Q

electron transport chain is the synthesis of ATP via what

where does ETC occur in the cell

each NADH produces how many ATP - how many protons pumped out
each FADH produces how many ATP - how many protons pumped out

what is the ultimate acceptor of electrons in the ETC

what is an important part of the ETC - what is it similar to

A

oxidative phosphorylation

inner mitochondrial membrane

NADH =  3 ATP and 6 protons pumped out 
FADH = 2 ATP and 4 protons pumped out 

oxygen

contains CoQ 10 which is similar to vitamin K

19
Q

what is the hypothesis which couples the ETC to the synthesis of ATP

A

chemiosmotic hypothesis

mitchell hypothesis

20
Q

what is another name for CoQ 10

structure is based on what

similar to what structure

what is its function of CoQ10

activates what complexes in ETC

naturally produced where

A

ubiquinone

based on cholesterol

similar to vitamin K

function - delivers oxygen to ETC

activates complex 1 2 and 3 in ETC

produced in the liver

21
Q

what step of ETC occurs in the mitochondrial matrix instead of the inner mitochondrial membrane

A

complex 2

succinate to fumarate

22
Q

where does gluconeogensis occur in the cell

except what step

stimulated by what
inhibited by what

primary precursors

enzymes

A

primarily in cytosol

conversion of pyruvate –> oxaloacetate –> malate occurs in the mitochondria - malate crosses mitchondrial membrane to cytosol - malate –> oxaloacetate –> phosphoenolpyruvate (PEPCK)

stimulated by glucagon and cortisol
inhibited by insulin

primary precursors - glycerol (from tags breakdown), lactate (cori cycle), amino acids (tca or pyruvate intermediates)

alanine <> pyruvate - alanine cycle
aspartate <> oxaloacetate - aspartate transamniase AST
glutamate <> alpha ketogarate - glutamate oxaloacetate transamniase GOT

pyruvate carboxylase - occurs in mitochondria* - requires biotin
PEP carboxykinase
fructose 1,6 bisphosphatase
glucose 6 phosphatase - only in liver*

23
Q

where is glycogen stored

what are the 2 different parts of glycogen metabolism

what are the major enzymes involved

what is each stimulated by or inhibited by

A

cytoplasm of liver and muscle

glycogen synthesis

  • glycogen synthase
  • stimulated by insulin and inhibited by glucagon
  • UDP glucose - important intermediate

glycogen degradation

  • glycogen phosphorylase
  • stimulated by glucagon and epinephrine and inhibited by insulin
24
Q

all transamniase reactions require what

A

B6

25
Q

what is the pentose phosphate pathway also known as

A

HMP shunt

phosphogluconate pathway

26
Q

where does the HMP shunt occur in the cell

what is the regulatory enzyme

what is the function of this pathway

energetics of HMP shunt

A

cytosol

regulatory enzyme - glucose 6 phosphate dehydrogenase

function

  • production of NADPH for both fatty acid synthesis and steroid hormone synthesis
  • production of ribose 5 phosphate for nucleotide synthesis

NO NET GAIN OR LOSS OF ATP

27
Q

what is another name for fatty acid synthesis and fatty acid degradation

A

fatty acid synthesis - lipogenesis

fatty acid degradation - lipolysis

28
Q

where does fatty acid synthesis occur in the cell

what is the regulatory enzyme

what is the hormonal regulation

what are the coenzymes

what kind of process is fatty acid synthesis

how does acetyl coA get to the cytosol from the mitochondria

A

cytosol

acetyl coA carboxylase

stimulated by insulin and inhibited by glucagon

coenzymes - NADPH from HMP shunt

fatty acid synthesis - REDUCTIVE PROCESS

cross mitchondria membrane as citrate

29
Q

where does fatty acid degration occur in the cell

what kind of process is fatty acid degradation

what is the regulatory enzyme

what is the hormonal regulation

what transports FA acids to mitochondria form the cystol - what is the precursor to this

A

mitochondrial matrix

beta oxidation

regulatory enzyme - hormone sensitive lipase
cleaves FA from TAGs in adipose

hormones - stimulated by epinephrine and inhibited by insulin

carnitine transports FA to mitochondria

lysine is precursor to carnitine

30
Q

where does the urea cycle occur in the cell

what is the nitrogen donor in the urea cycle

what is the rate limiting enzyme

what are the important intermediates to the urea cycle

A

occurs in both the cytosol and mitochondria

glutamate gives urea its 2 nitrogen atoms

carbamoyl phosphate synthase - in mitochondria and forms carbomoyl phosphate

ARCO
arginine
citrulline
ornitine